The present invention relates generally to stripline and microstrip electronic circuits and more particularly to electronic circuits that provide protection from transients generated by electrical surges and electromagnetic (EM) phenomena such as lightning.
Communications equipment, computers, home stereo amplifiers, televisions, and other electronic devices are manufactured using small electronic components that are very vulnerable to damage from electrical energy surges. Surge variations in transmission line power and voltages, as well as noise, can change the operating range of the equipment and can severely damage and/or destroy electronic components and devices. Moreover, these electronic components and devices can be very expensive to repair and replace.
There are many sources that can cause harmful electrical energy surges. One source is radio frequency (RF) interference that can be coupled to power and transmission lines from a multitude of sources. The power and transmission lines act as large antennas that may extend over several miles, thereby collecting a significant amount of RF noise from such sources as radio broadcast antennas. Another source of the harmful electrical energy is power surges caused by power outages or loss in power to a particular electronic component. In some instances, power to an electronic component is lost and thereafter restored causing a surge to travel across a computer board. Another harmful source is conductive noise, which is generated by equipment connected to the power and transmission lines and which is conducted along the power lines to the equipment to be protected. Still another source of harmful electrical energy is lightning. Lightning is complex electromagnetic energy source having potentials estimated at from 5 million to 20 million volts and currents reaching thousands of amperes.
Ideally, what is needed is an electronic component having a low insertion loss, a low voltage standing wave ratio (VSWR), and a compact size that can be mounted on a circuit board, i.e., a RF board, to provide surge protection.